One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,19)(12,17)(13,23)(14,15)(16,20)(18,24)(21,22)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,40)(37,38) involution — undirected(1,2,5,4)(3,7,8,6)(10,15)(12,22)(16,19)(18,23)(25,27,31,28)(26,32,30,33)(29,36,37,35)(34,40,38,39)(1,3,5,8)(2,6,4,7)(10,15)(11,20)(12,22)(13,24)(26,30)(27,28)(29,37)(39,40)(3,8)(6,7)(9,11)(10,16)(12,23)(13,21)(14,20)(15,19)(17,24)(18,22)(25,28,31,27)(26,33,30,32)(29,35,37,36)(34,39,38,40)(1,3)(2,7)(4,6)(5,8)(9,12,14,22)(10,17,15,21)(11,18,20,23)(13,19,24,16)(25,29,31,37)(26,34,30,38)(27,35,28,36)(32,39,33,40)(1,4,5,2)(3,6,8,7)(9,13)(10,18)(11,21)(12,19)(14,24)(15,23)(16,22)(17,20)(25,30,31,26)(27,33,28,32)(29,38,37,34)(35,40,36,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.